Researchers at Aalto University and the University of Jyväskylä showed that graphene can be a superconductor at a much higher temperature than expected, due to a subtle quantum mechanics effect of graphene's electrons.
The discovery of the superconducting state in twisted bilayer graphene spurred an intense debate among physicists regarding the origin of superconductivity in graphene. Although superconductivity was found only at a few degrees above the absolute zero of temperature, uncovering its origin could help understanding high-temperature superconductors and allow us to produce superconductors that operate near room temperature. Such a discovery has been considered one of the "holy grails" of physics, as it would allow operating computers with radically smaller energy consumption than today.
The new work came from a collaboration between Päivi Törmä's group at Aalto University and Tero Heikkilä's group at the University of Jyväskylä. Both have studied the types of unusual superconductivity most likely found in graphene for several years.
"The geometric effect of the wave functions on superconductivity was discovered and studied in my group in several model systems. In this project it was exciting to see how these studies link to real materials," says the main author of the work, Aleksi Julku from Aalto University. "Besides showing the relevance of the geometric effect of the wave functions, our theory also predicts a number of observations that the experimentalists can check," explains Teemu Peltonen from the University of Jyväskylä.